Add a special timer that counts down when you enter a room or when a linedef gets executed.
This timer should be at the top, middle with red text that counts down. When the timer reaches zero, kill the player. Make sure that this is easy to set up the time and be able to start, stop, and reset the timer with ease. I don't want to make a million sectors If the place you get trapped in has many rooms. (If using sector types like the check number of rings linedef)
Also, Add a global timer that will count down and when it reaches zero, the player dies. It should start from what you set it as in the level header or something like that.
Add some textures that are like the hologram room from star trek and stuff like that so people can make neat techno-type levels.
Sonict